Disclosed herein are alizarin-based polymer colorants comprising polymer monomer units and alizarin units, compositions, latex, and toners comprising the polymer colorants, and processes for producing same. The alizarin-based polymer colorants and polymer compositions are bio-based, are naturally colored and do not need any additional colorant, dye or pigment. The polymer colorants and polymer compositions may be used for the formation of assorted articles and materials including, in embodiments, toners.
Numerous processes are within the purview of those skilled in the art for the preparation of toners. Emulsion aggregation is one such method. Emulsion aggregation toners may be used in forming print and/or electrophotographic images. Emulsion aggregation techniques may involve the formation of a polymer emulsion by heating a monomer and undertaking a batch or semi-continuous emulsion polymerization, as disclosed in, for example, U.S. Pat. No. 5,853,943, the disclosure of which is hereby incorporated by reference in its entirety. Emulsion aggregation/coalescing processes for the preparation of toners are illustrated in a number of patents, such as U.S. Pat. Nos. 5,290,654, 5,278,020, 5,308,734, 5,344,738, 6,593,049, 6,743,559, 6,756,176, 6,830,860, 7,029,817, and 7,329,476, and U.S. Patent Application Publication Nos. 2006/0216626, 2008/0107989, 2008/0107990, 2008/0236446, and 2009/0047593. The disclosures of each of the foregoing patents are hereby incorporated by reference in their entirety.
Polyester EA ultra low melt (ULM) toners have been prepared utilizing amorphous and crystalline polyester resins as illustrated, for example, in U.S. Patent Application Publication No. 2008/0153027, the disclosure of which is hereby incorporated by reference in its entirety.
Many polymeric materials utilized in the formation of toners are based upon the extraction and processing of fossil fuels, leading ultimately to increases in greenhouse gases and accumulation of non-degradable materials in the environment. Furthermore, current polyester based toners may be derived from a bisphenol a monomer, which is a known carcinogen/endocrine disruptor.
Bio-based polyester resins have been utilized to reduce the need for this carcinogenic monomer. An example, as disclosed in co-pending U.S. Patent Application Publication No. 2009/0155703, includes a toner having particles of a bio-based resin, such as, for example, a semi-crystalline biodegradable polyester resin including polyhydroxyalkanoates, wherein the toner is prepared by an emulsion aggregation process.
Most consumer goods require to be colored. Color is typically provided by pigments and dyes including colored marking materials such as toners and inks. While small molecule dyes or pigments have significant advantages, including favorable cost, ease of manufacturing, and in some cases enhanced lightfastness, they can also have disadvantages. Dispersing of pigments can be a time and energy consuming process requiring tedious selection of surfactant, synergist additives and particle size reduction experimental conditions. In addition, because of a tendency to settle, the stability of pigment dispersions can be problem over industries using colorants, including inks, paints, toners or colored extruded product parts. For example, in emulsion aggregation toner fabrication, the pigment can be added during the emulsion-aggregation process to provide color to the toner particles. Pigments can be rejected during the emulsion aggregation process and/or washing stage of the toner making process thereby changing the final color of the toner. Small molecule dyes can also have limitations. Dye migration, poor thermal and lightfastness properties are problems that can be encountered with small molecule dyes. These issues can impact a variety of industries such as plastic dishware and toys which are first compounded by polymer extrusion and then have colorant added during the article shaping. Many coloring agents soften, melt or decompose at temperatures below the melting point of the high temperature polymer used for the article and the colorants can then adhere to the extruder parts causing the final polymeric product to have inconsistent color.
While currently available colorants and toners are suitable for their intended purposes, a need remains for improved colorants. Further, a need remains for improved colored polymer compositions, latex, and toner compositions. Alternative cost-effective, environmentally friendly toners remain desirable. Furthermore, there is a need for sustainable, bio-based colorants and resin compositions and for sustainable, bio-based products. There is further a need for marking materials having increased content of bio-renewable components including sustainable colorants. There is further a need for a colorant material which provides robust colors with improved lightfastness, thermal and temporal stability and which is bio-renewable.
The appropriate components and process aspects of the each of the foregoing U.S. Patents and Patent Publications may be selected for the present disclosure in embodiments thereof. Further, throughout this application, various publications, patents, and published patent applications are referred to by an identifying citation. The disclosures of the publications, patents, and published patent applications referenced in this application are hereby incorporated by reference into the present disclosure to more fully describe the state of the art to which this invention pertains.